1. Field of the Invention
The present invention generally relates to an acrylic composition and a method of forming the acrylic composition via free-radical polymerization. More particularly, the present invention relates to an acrylic composition that can be incorporated into a coating composition and then used in various coating applications, such as an automotive coating application, to produce films that have suitable scratch, mar, and chip performance.
2. Description of the Related Art
Acrylic compositions and their use in a wide variety of coating applications are known in the art. In a coating composition, acrylic compositions, along with a suitable cross-linking agent, are designed to produce a film having good film properties, such as resistance to scratch, mar, and chip. Coating compositions that utilize acrylic compositions typically require solvents to dissolve or otherwise reduce the acrylic composition, thus rendering the acrylic composition less viscous for optimum processing and application purposes. Solvents are required primarily due to a high molecular weight and a correspondingly high viscosity for the acrylic composition.
It is known that there is a movement toward utilizing acrylic compositions that have lower molecular weights so as to reduce the overall amount of solvents, i.e., volatile organic compounds (VOCs), required in the coating composition. However, it is also known that coating compositions that utilize acrylic compositions with lower molecular weights produce films that have poorer film properties as evidenced by decreased scratch, mar, and chip performance.
Highly branched, i.e. star, compositions are being utilized more frequently because they offer higher molecular weights yet they exhibit low viscosity, as compared to the viscosity of acrylic compositions, i.e., acrylic compositions that are not highly branched. To date, these highly branched compositions have primarily been polyester-based. However, some highly branched acrylic compositions have been developed by complex methods such as Atom Transfer Radical Polymerization (ATRP) and Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization. These methods are complex, and are therefore generally undesirable for a variety of reasons including, but not limited to, slow reaction times, poor manufacturability, use of metal or sulfur-containing compounds, and a requirement for post purification of the acrylic composition.
Due to the inadequacies associated with the acrylic compositions of the prior art, especially the highly branched acrylic compositions developed by ATRP and RAFT, it is desirable to provide a new and unique acrylic composition and a relatively non-complex method to form the acrylic composition.